Measuring packet loss

  The rate at which packets are lost can have a dramatic impact on application performance. For example, it has been shown that for moderate loss rates (less than 15 percent) the bandwidth delivered by TCP is proportional to $1/\sqrt lossrate$ [MSM97]. Similarly, some streaming media applications only perform adequately under low loss conditions [CB97]. Not surprisingly, there has always been a long-standing operational need to measure packet loss; the popular ping tool was developed less than a year after the creation of the Internet. In the remainder of this section we'll discuss two dominant methods for measuring packet loss: tools based on the Internet Control Message Protocol (ICMP) [Pos81] and new measurement infrastructures.